A recent article written in WebMD by Dennis Thompson titled "Big Outdoor Temp Swings Tied to Heart Attack Risk" examined the correlation between large temperature swings and heart attacks.
The article which appeared March 1, 2018 acknowledged that "many people know that extreme cold can raise your chances of having a heart attack, but that a new study suggests that wild swings in temperature may do the same."
According to the research cited by the article "the greater the temperature change during the course of a single day, the more people show up at the hospital in need of emergency surgery for a heart attack.
The risk of heart attack seems to increase by about 5 percent for every 9 degrees Fahrenheit of temperature swing on a given day.
This risk appears to crop up mainly during warmer weather, with the most marked effect occurring on days with an average temperature of 86 degrees."
Investigators used a database that tracks all patients in Michigan who under went an emergency procedure to open blocked arteries during a heart attack.
Their analysis revealed that swings of more than 45 degrees Fahrenheit were associated with a greater increase in heart attack rates compared with swings of 18 to 45 degrees.
A swing of more than 30 degrees Fahrenheit in a single day appears to cause a more than 10 percent increase in the proportion of heart attacks that take place, compared to days when the temperature remains relatively stable
According to their analysis "there were more days in which the temperature swung from warm to cold than the other way around. Given that, one potential explanation for the apparent increased risk could be the effects of a sudden chill on the heart and blood vessels."
When it came to the effects of Global Warming the research team stated that the jury was still out.
“Overall, warmer days and nights could lead to a reduced difference between maximum and minimum temperature, which would decrease the risk of heart attack.
On the other hand, global warming might cause an increase in extreme weather events featuring wildly fluctuating temperatures, which might cause the risk to rise."
The article concludes by saying " researchers should consider looking farther back into the historical record, to see if they can uncover similar effects on heart attack cases based on temperature changes in other places."